This invention relates to a cap for a container, and more particularly to a novel pouring spout to facilitate the withdrawal of a liquid from a container, such as a body fluid from a test tube and the like.
Evacuated tubes are routinely used for the collection of blood specimens and transportation to laboratory for analysis. Much analysis involves the separation of blood into its light and heavy phases by centrifugation. Simple collection procedure requires that the serum be promptly transferred to another tube to prevent the continuing interaction of the blood components.
Serum separation tubes such as described in U.S. Pat. No. 3,852,194 to A. R. Zine, Jr., achieve prompt separation of the blood components by means of a barrier material which is brought into place between the blood phases during centrifugation. This permits the liquid phase to be stored in the orginal container with the obvious benefits in cost and sample identification. Since the stopper is generally discarded when the first sample is aliquoted, the tube will often remain uncovered until the final sample is taken and the tube covered for long term storage.
In order to aliquot uncontaminated specimens without spillage, a number of transfer devices are frequently used such as pipettes and filter devices. It is important that pipettes be discarded immediately after use to prevent cross contamination with another specimen. Depending on the particular procedures used in the laboratory, this will often result in the use of more than one pipette.
Conversely, use of tubes with barrier materials permits storage on the barrier without the necessity of decanting the serum.